Cooling means for conductors



Dec. l18, 1934. c. M, LAFFooN ET AL 1,985,040

COOLING MEANS FOR CONDUG'TORS Filed Jan. 14, 1953 2 Sheets-Sheet l n .Il (For H TLN INVENTORS Carib/"ae M af/aan Ben/7i@ A. R056.

` AT'TORNEY l l l l l l MLN .Smm

WITNESSES:

fau/ l DCC.I18, C. M, L AFFON ET AL 1,985,040

COOLING MEANS FOR CONDUCTORS Filed Jan. 14, 1933 2 Sheets-Sheet 2 BY 09M M ATTORNEY Patented Dec. 1s, 1934 l A' 1,985,040

yUNITED?-SinfrEsfv PATENT OFFICE COOLING MEANSFOR CONDUCTORS CarthraeM. Laffoon, Irwin, and Bennie A. Rose,

Swissvale, Pa., assignors to Westinghouse Electric & vManufacturing Company, East `Pittsburgh, Pa., acorporation ofv Pennsylvania :Application january 14, 1933, Serial No. 651,660

" 1o claims. (c1. 1v1- 252) This invention'relates to means 'for cooling Fig. 6 is a Yfragmentary sectional View taken electrical machinery, and more particularly to on vthe line Vi-VI, i. e., at right angles to the means for cooling the rotor oi a turbo electric showing in Fig. 5; Vand generator. f i Fig. i is a perspective view of a two pole rotor '5 Conductors embedded in the slots of a turbo of a turbo-generator villustrating the modiiica- 5 rotor are surrounded; by a comparatively thick tion shown in Figs. 3 and 4 applied to the rotor. covering of insulating material; This material Referring t the drawings, Figs. 1 and 2 ShOW forms a Very Strong hindrance .to the escape of arotor 1 (onlya fragmentary View being shown) heat to the-outsideand correspondingly-reduces having Vslots 2 inl the lperiphery thereof. Con- 1'() the eiiiciency ofthe machine. Hollow conducduits 3 extend parallel to the axis of the rotor l 10 tors have been proposed which increase' the effiand are connected to the slots 2 by radially exciency ofthe machine somewhat,v but such contending passages 4. A plurality of conductors 5 ductors have not proved practical because of of` rectangular cross-section .are disposed one the increased resistance due to the smaller cross upon lthe other in the slots 2 and insulated from v sectional area of the conductor and the greater each other by thin layers of insulation l2. An l5 cross-sectional slot area necessary. insulating Wall `orfvvrapping 6 surrounds all of Accordingly, one object of this invention is to the conductors 5 and added insulation '7 is proprovide cooling means for the conductors of a vided at the top and bottom oi the slots 2 in rotor which permit the cooling air to come in order to increase the creepage distance from the direct contact with the bare copper of the conductors 5 to the iron of the rotor 1. A wedge 20 conductors. l' 8 of' a suitable insulating material holds the Another object ofthis invention is to provide conductors 5 in the slot 2 and extra insulation 9 a vnovel cooling means forthe conductors oi a isprovided between the Wedge 8 and the conrotor which shall be simple in construction and ductors 5. economical 'to manufacture. The conductors 5 and the wedge 8 have aligned 25 A further object ofthis invention is to reduce apertures 10 and 11, respectively, which extend the ltemperature drop from the bare copper of radially from the spaced passages 4 and thus a rotor conductor to the outsideair. provide a cooling passage from the longitudinal- A still further object of this invention is to ly 'extending conduits 3 to the outer periphery or increase the maximum'output that can be ob-` the rotor `1. The longitudinally extending eon- 30 tained from a turbo generator with given duits 3 andthe radially extending passages 4, 10 physical dimensions. and-11 permit the air to pass from the central A broad object of this invention is to increase part of the rotor 1l through the conductors 5 and the ampere turn rating of a rotor. l the Wedge 8 to the outside. The apertures 10 Other objects of this invention will become Within the conductors 5 may be rectangular or 35 evident from the'follovving detailed description, oblong and may be placed every six or eight taken in conjunction with the accompanying inches apart. The apertures 11 are, however, drawings, inmwhich:V circular so as not to weaken the wedge 8 too Figure 1 isa fragmentary'sectional view of a much. The insulation 9 provides the change 40 slot taken in a plane longitudinally of the slot from a rectangular to a circular section. 40 of apart oi an electric machine, such as the With the arrangement explained, practically ro'tor of a turbo-generator, with conductors' emall of the field copper losses would flow to the bedded therein according to this invention; ducts and the temperature drop through the lFig. 2 is a fragmentary sectional view taken eld coil insulation 6 and 7 would be eliminated. on line lI-II ofy Fig. 1, i. e., at right angles to Furthermore, the temperature drop from the 45 the section shown in Fig. 1; bare copper to the cooling air would be reduced Fig. 3 is -ag fragmentary sectional view taken since the. duct'dimensions can be proportioned similarly to Fig. 1 ofV a modification of the structo give a large cooling perimeter for a given ture shown in Fig. l; area of section. In the arrangement shown, rel- Fig. 4 iS a fragmentary sectional view taken atively large creepage distances are obtained, 50 on the line IV-IV of Fig. 3; and there is no reduction in the slot space due to Fig. 5 ShOWS 9 fragmentary Sectional View the addition of the insulation. taken longitudinally 0f the end Winding of a In Figs. 3 and 4, a rotor 20 is provided with rotor of a turbo-generator having Cooling means slots 21 extending substantially longitudinally provided therein according to this invention; thereof. Conductors 22 insulated from each oth- 5 5 er by a thin layer of insulation 29 covering each conductor are disposed one upon the other in the slots 21 and are surrounded by an insulating wall or wrapping 42. An additional strip of insulation 23 is provided at the top and bottom of the slots 21 in order to increase the creepage distance from the conductors 22 to the iron of the rotor 20. A Wedge 24 of suitable insulating material holds the conductors 22 in the slots 21 and extra insulation 25 is provided between the wedge 24 and the conductors 22. A slot 26 of less width than slot 21 is cut in the bottom of each slot 21. This slot 26 extends the full length of the armature and is open at the end and communicates with all the radial apertures 27. Ventilation for the conductors 22 is thus provided.

These rectangular or oblong apertures 27 provided in the conductors 22, for an average size generator, are spaced every six or eight inches apart along the conductors 22. The apertures 27 are aligned with circular apertures 28 provided in the Wedges 24, thereby connecting the inner slot 26 with the outer periphery of the rotor 1. With this arrangement, air is drawn or forced into the inner slot 26 and passed out through the slots 27 and 23, carrying the heat from the conductors 22 with it.

The end windings of a turbo-generator rotor are shown in Figs. and 6 and may be alike for both the modications shown in Figs. 1 to 4, inclusive. The plurality of conductors 5 insulated from each other by insulation 12 are disposed in Winding channels 31 held in place by a retaining ring 32. Insulation 33 is provided in the top of the winding channels 3l and all the conductors 5 are wrapped in the insulation 6. Insulation 34 is also provided between the re taing ring 32 and the Winding channel 31. The apertures extend through the conductors 5, the winding channel 31, and the retaining ring 32. Air passes through the apertures 10 to the outer periphery of the retaining ring 32 carrying the heat from the conductors 5 with it. The apertures 10 Within the conductors 5 may be oblong or rectangular and are conveniently spaced to provide sufcient cooling area.

Although the foregoing description relates to certain specific embodiments, it is apparent that many modications thereof are possible and may be devised by those skilled in the art after having studied this invention, the invention is, therefore, not to be restricted except insofar as is necessitated by the prior art and the spirit of the appended claims.

We claim as our invention:

1. In a rotor of a dynamo-electric machine having slots, conductors disposed in said slots, said conductors having apertures extending transversely through, and surrounded by the metal of, said conductors and spaced longitudinally thereof for cooling said conductors.

2. In a rotor of a turbo generator, slots extending substantially longitudinally of said rotor, and insulated conductors disposed in said slots, said conductors having small apertures extending transversely therethrough and spaced longitudinally thereof for cooling said conductors.

3. In a rotor' o'f a. turbo-generator having longitudinally extending conduits interiorly thereof, slots substantially parallel to said conduits in the periphery of said rotor, and conductors disposed Within said slots, said conductors being pierced by transverse openings communicating with said conduits to provide vent passages from the interior of said rotor to the outer periphery thereof for cooling Vsaid conductors.

4. In a. rotor of a turbo-generator having cornparatively large slots in the periphery thereof and extending substantially longitudinally thereof and smaller slots formed in the bottom of said larger slots, and insulated conductors disposed in said peripheral slots, said conductors having small-diameter radial passages extending therethrough for providing vent openings from the smaller slots to the outer periphery of said rotor.

5. In a rotor of a turbo-generator having longitudinally extending conduits interiorly thereof, slots in the periphery of said rotor, a plurality of conductors disposed one upon the other within said slots, and wedges for retaining said conductors within said slots, said conductors and said wedges having apertures extending transversely therethrough to provide vent openings from said interior conduits of said rotor to the outer periphery thereof.

6. In combination with a turbo-generator rotor having longitudinally thereof slots, conductors disposed in said slots and extending around the ends of said rotor, said conductors having spaced small-diameter apertures extending transversely therethrough, and a retaining ring for holding said conductors extending around the ends of said rotor in place, said retaining ring having apertures aligned with the apertures in said conductors to permit air to pass therethrough.

7. A dynamo-electric machine rotor designed to receive a plurality of conductors in the periphery thereof, said conductors having spaced vent holes transverse thereof and surrounded by the metal of said conductors.

8. The combination of a slotted rotor of a dynamo-electric machine and .a plurality of form-wound conductors insulated from each other and all wrapped in an insulating shield to form a coil, the shape of the coil being such as to fit in the rotor slots of a dynamo-electric machine, said conductors being pierced by aligned spaced vent openings transversely thereof and extending over the entire coil.

9. A conductor in combination with the rotor of a dynamo-electric machine, said conductor having small transverse vent openings spaced overv the entire length of the conductor.

10. A rotor having longitudinal and radial vent openings communicating with each other, in combination, a conductor disposed on the rotor and pierced by transverse vent openings aligned with said radial vent openings whereby the conductor is effectively cooled when the rotor is rotating.

CARTHRAE M. LAFFOON. BENNIE A. ROSE. 

